NEW ORLEANS — Much of the talk leading up to Super Bowl XLVII was about the coaching Harbaugh brothers, San Francisco's Jim and Baltimore's John, and the historic spin they put on the NFL's splashiest showcase.

But the outcome Sunday hinges on the unrelated brothers in arms, Colin Kaepernick of the 49ers and Joe Flacco of the Ravens, quarterbacks of contrasting styles, and how they handle the biggest game of their lives.

Kaepernick is a sculpted, 6-foot-4 nightmare for a defense, a second-year player with the speed of a sprinter and a pitcher's right arm. He's the quintessential dual threat, whose post-snap intentions are as hard to read as the tattooed Bible verses that run up and down his biceps.

The 6-foot-6 Flacco is only 28, and he's already an old-school throwback. Although he's far from immobile, he's much more of a drop-back pocket dweller than his Super Bowl counterpart. And lately, he's on fire. In Baltimore's path back to the sport's marquee game — victories over Indianapolis, Denver and New England — Flacco has eight touchdown passes with no interceptions.

The Ravens, with Flacco at quarterback, have gotten to the playoffs each of the last five seasons, a feat no other NFL team has accomplished. What's more, Baltimore has won at least one postseason game in each of those years.

In this copycat league, the quarterback who hoists the Lombardi Trophy at the end of this game will be Exhibit A for two opposing football philosophies.

Does this league belong to the runners, or the gunners?

Steve Young, the last quarterback to win a Super Bowl for the 49ers, and a Hall of Fame player who wasn't shy about tucking the football and running, believes we're witnessing a fascinating historical hiccup. By his thinking, the Kaepernick-style quarterbacks — players such as Seattle's Russell Wilson, Washington's Robert Griffin III and Carolina's Cam Newton — eventually will log more pocket time than a stingy man's wallet.

"Sooner or later, you get straightened up to the fact that to deliver championship football, it's from the pocket," said Young, now an ESPN analyst, who capped the 1994 season by securing a fifth championship for the 49ers.

"I might be proven wrong, but I think we have a special gap in time. There's something unique happening, and I think it will close. Will it completely close? No. And I think that young, mobile quarterbacks will become more valuable now rather than in the past, and maybe become the prototype."

But, Young said, the ability to shred a defense with the run "can never be the full measure of what quarterbacks need to do in the league." That's why players such as Kaepernick, Wilson and Griffin — all of whom can pass, all of whom made the playoffs this season — are offensive cornerstones, and the one-dimensional Tim Tebow is not.

Flacco, whose own father describes him as "dull," is one of the more exciting passers in football because he throws the risky passes, the ones that tickle the fingertips of defenders but ultimately rest in the hands of his receivers. From his bombs to his back-shoulder throws to his darts he could wedge through a mouse hole, Flacco takes chances.

In three games this postseason, Flacco has completed 54.8% of his throws for 853 yards and a lofty overall passer rating of 114.7. He has thrown 162 passes without an interception, his last coming in a Dec. 16 loss to Denver. He's not a dink-and-dunk quarterback; he's completed 15 passes of 20 or more yards in the three playoff games.

"He's a guy that was always in constant control," said K.C. Keeler, Flacco's college coach at Delaware. "And I asked him one day, 'OK, I'm going to talk to a youth group someday about you, what made you great. What makes you great?' And he goes, 'I'm not afraid to fail. It's that simple. I'm going to prepare as hard as I can, and I'm going to go out there, and it doesn't matter what the arena is, I'm just going to go play. And if we're successful, great. And if we're not? I'll live with it. But I'm not afraid to fail.'

"When you watch Joe play, you just wonder, 'How does he stay so calm?' Well, that's how he was brought up. This isn't something that I instilled in him or any other coach did. His parents just did such a great job of their simple messages. And that simple message of not being afraid to fail is the reason he's playing in this big ballgame now."

Flacco might not be afraid to fail, but, in the NFL, the stakes can't get any higher than Sunday's game.

Both of these teams were turned back at the altar last season — Baltimore came within a dropped touchdown pass of beating New England in the AFC championship game, and San Francisco fumbled away its NFC title chances in an overtime loss at home to the New York Giants.